Final Results: PWR MOX/UO 2 Control Rod Eject Benchmark

Transcription

1 Final Results: PWR MOX/UO 2 Control Rod Eject Benchmark T. Kozlowski T. J. Downar Purdue University January 25, 2006 This work has been sponsored by the U.S. Nuclear Regulatory Commission. The views expressed herein are strictly those of the authors, and do not represent U.S. NRC staff position.

2 Benchmark Description Background Proposed by U.S. NRC / RES in 2001 as part of Pu Disposition Research Sponsored by U.S. NRC (Purdue) and OECD/NEA Motivation Assessment of heterogeneous transport and nodal diffusion transient methods for MOX RIA Comparison of MOX/UO 2 and UO 2 core transient response to CEA Numerical Benchmark Based on 4-loop Westinghouse PWR reactor Steady-state at HZP and HFP conditions Transient Rod Eject from HZP conditions Heterogeneous Reference Solution (DeCART 47G MOC) 2

3 Benchmark Description (Cont.) Group constants provided 2G assembly homogenized XS with ADF and pin power form functions 4G assembly homogenized XS with ADF and pin power form functions 8G assembly homogenized XS with ADF and pin power form functions Number densities for heterogeneous calculation Benchmark conditions Reactivity insertion problem (important for Weapons Pu transient w/ small B-eff) Initial HZP conditions, critical boron concentration, CR ejected from the full core Compare: Eigenvalue Assembly and Pin Power distribution CR worth Transient power, reactivity and fuel temperature 3

4 OECD/NRC MOX Rod Ejection Benchmark: Core Loading Pattern U 4.2% U 4.2% U 4.2% U 4.5% U 4.5% M 4.3% U 4.5% U 4.2% A (CR-D) (CR-A) (CR-SD) (CR-C) B U 4.2% U 4.2% U 4.5% M 4.0% U 4.2% U 4.2% M 4.0% U 4.5% (CR-SB) U 4.2% U 4.5% U 4.2% U 4.2% U 4.2% M 4.3% U 4.5% M 4.3% C (CR-A) (CR-C) (CR-B) D U 4.5% M 4.0% U 4.2% M 4.0% U 4.2% U 4.5% M 4.3% U 4.5% (CR-SC) U 4.5% U 4.2% U 4.2% U 4.2% U 4.2% U 4.5% U 4.2% E (CR-SD) (CR-D) (CR-SA) M 4.3% U 4.2% M 4.3% U 4.5% U 4.5% M 4.3% U 4.5% F (CR-SB) (CR-SC) U 4.5% M 4.0% U 4.5% M 4.3% U 4.2% U 4.5% Assembly Type G (CR-C) (CR-B) (CR-SA) CR Position Burnup [GWd/t] U 4.2% U 4.5% M 4.3% U 4.5% Fresh H Once Burn Twice Burn Note: 27% of the assemblies are MOX 4

5 Assembly Design UOX Fuel UOX IFBA Fuel Guide Tube or Control Rod Guide Tube MOX 2.5 % MOX 3.0% MOX 4.5 or 5.0% WABA Pin Guide Tube 5

6 Refueling Strategy Assembly Type Fresh Fuel Once Burned Twice Burned 0 GWd/tHM 20.0 GWd/tHM 35.0 GWd/tHM UOX 4.2% UOX 4.5% MOX 4.0% MOX 4.3% Total Note: 27% of the assemblies are MOX 6

7 Fuel Composition Assembly Density Type [g/cm 3 ] HM Material UOX 4.2% U-235: 4.2 w/o, U-238: 95.8 w/o UOX 4.5% MOX 4.0% U-235: 4.5 w/o, U-238: 95.5 w/o Corner zone: 2.5 w/o Pu-fissile Peripheral zone: 3.0 w/o Pu-fissile MOX 4.3% Central zone: 4.5 w/o Pu-fissile Corner zone: 2.5 w/o Pu-fissile Peripheral zone: 3.0 w/o Pu-fissile Central zone: 5.0 w/o Pu-fissile Uranium vector: 234/235/236/238 = 0.002/0.2/0.001/ w/o Plutonium vector: 239/240/241/242 = 93.6/5.9/0.4/0.1 w/o 7

8 Sample Fuel Number Densities Format HELIOS Identifier E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E 06 8

9 Benchmark Calculations Part 1: Fixed T/H conditions: HZP ARO and HZP ARI, 1000 ppmb (2D) k eff assembly and pin power distribution rod worth Part 2: Operating conditions: HFP, ARO (3D) critical boron concentration assembly and pin power distribution Part 3: Beginning of transient conditions: HZP, partly rodded (3D) critical boron concentration assembly and pin power distribution Part 4: Rod ejection transient (3D) Ejection of the highest worth rod from conditions calculated in Part 3 9

10 Benchmark Conditions HFP % rated power (3565 MW) inlet coolant temperature of 560 K inlet pressure of 15.5 MPa HZP 1.0e-4 % rated power (3565 W) inlet coolant temperature of 560 K inlet pressure of 15.5 MPa Transient ejection of highest worth rod at HZP ARI, critical boron concentration rod fully ejected in 0.1 sections no reactor scram after the ejection boron concentration in the position of the other control rods are constant. 10

11 Benchmark Participants and Submitted Homogeneous Solutions Nodal solutions Code, unique solution label CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH Organization (Country) PSI (Switzerland) PSI (Switzerland) Osaka University (Japan) KAERI (Korea) Purdue Univ. (USA) Purdue Univ. (USA) Purdue Univ. (USA) JNES (Japan) Solution method Nodal diffusion Nodal diffusion Nodal diffusion Nodal diffusion Nodal diffusion Nodal diffusion Nodal diffusion Nodal diffusion Groups/ Homogenization 2G Nodal 2G Nodal 2G Nodal 2G Nodal 2G Nodal 4G Nodal 8G Nodal 2G Nodal Cross section library 2G benchmark library 2G benchmark library 2G benchmark library 2G benchmark library 2G benchmark library 4G benchmark library 8G benchmark library 2G benchmark library 11

12 Benchmark Participants and Submitted Heterogeneous Solutions Heterogeneous solutions Code, unique solution label Organization (Country) BARS Kurchatov Inst. (Russia) DeCART SNU/KAERI (Korea) DORT GRS (Germany) MCNP Kurchatov Inst. (Russia) Solution method Lambda matrix MOC S N Monte Carlo Groups/ Homogenization 5G Cell hom 47G Cell het 16G Cell hom Continuous Cell het Cross section library UNK generated HELIOS based HELIOS generated ENDF/B-VI with NJOY 12

13 Part 1, 2D fixed T/H Eigenvalue and Assembly Power Comparison Eigenvalue Todal Rod Assembly Power Error Worth ARO ARI ARO ARI [dk/k] %PWE %EWE %PWE %EWE nodal CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH heterogeneous BARS DeCART ref ref ref ref DORT MCNP Max. difference ei refi PWE = ref Power-Weighted Error (PWE) Error-Weighted Error (EWE) EWE = i i i i e i e e i i i calci refi ei = 100 ref i 13

14 Part 1, 2D fixed T/H Pin Power Comparison ARO Assembly Position (A,1) (B,2) (C,3) (D,4) (E,5) (F,6) nodal CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH heterogeneous BARS DeCART ref ref ref ref ref ref DORT MCNP

15 Part 1, 2D fixed T/H Pin Power Comparison ARI Assembly Position (A,1) (B,2) (C,3) (D,4) (E,5) (F,6) nodal CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH heterogeneous BARS DeCART ref ref ref ref ref ref DORT MCNP

16 Part 2, 3D Hot Full Power Eigenvalue, Assembly Power, T/H Conditions Critical Assembly Power Error Core Average T/H Properties Boron Doppler Moderator ModeratorOutlet ModOutlet Mod. Concent. %PWE %EWE Temp. Density Temp. Density Temp. [ppm] [K] [g/cm3] [K] [g/cm3] [K] nodal CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G 1679 ref ref PARCS 4G PARCS 8G SKETCH Max. difference

17 Part 2, 3D Hot Full Power Pin Power Comparison Assembly Position (A,1) (B,2) (C,3) (D,4) (E,5) (F,6) nodal CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G ref ref ref ref ref ref PARCS 4G PARCS 8G SKETCH

18 Part 2, 3D Hot Full Power Axial Power CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH Relative Power [-] Axial Height [cm] 18

19 Part 3, 3D Hot Zero Power Critical Boron Concentration, Delayed Neutron Fraction and Assembly Power Comparison Critical Delayed Assembly Boron Neutron Power Concent. Fraction Error [ppm] [pcm] %PWE %EWE nodal CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH heterogeneous BARS DeCART ref ref Max. difference

20 Part 3, 3D Hot Zero Power Pin Power Comparison Assembly Position (A,1) (B,2) (C,3) (D,4) (E,5) (F,6) nodal CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH heterogeneous BARS DeCART ref ref ref ref ref ref 20

21 Part 3, 3D Hot Zero Power Axial Power 1.6 Relative Power [-] CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH BARS DeCART Axial Height [cm] 21

22 Part 4, 3D Transient Integral Parameter Comparison Peak Peak Peak Power Time Power Reactivity Integral [sec] [%] [$] [%-sec] nodal CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH heterogeneous BARS Max. difference

23 Part 4, 3D Transient Core Power and Reactivity Core Power [%] CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH BARS Reactivity [$] CORETRAN 1/FA CORETRAN 4/FA EPISODE N/A PARCS 2G PARCS 4G PARCS 8G SKETCH BARS Time [sec] Time [sec] 23

24 Part 4, 3D Transient Assembly and Point Pin Peaking Assembly Peaking [fxy] CORETRAN 1/FA CORETRAN 4/FA N/A NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH BARS Point-Pin Peaking [fq] CORETRAN 1/FA N/A N/A NUREC PARCS 2G N/A N/A SKETCH BARS Time [sec] Time [sec] 24

25 Part 4, 3D Transient Moderator Temperature and Density Core Average Moderator Temperature [K] CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH BARS Core Average Moderator Density [kg/m3] CORETRAN 1/FA CORETRAN 4/FA EPISODE NUREC PARCS 2G PARCS 4G PARCS 8G SKETCH BARS Time [sec] Time [sec] 25

26 Conclusions Nodal diffusion codes are capable of modeling static MOX core 1-2% assembly and pin-power error at ARO 2-4% assembly and pin-power error at ARI Nodal diffusion codes are consistent in modeling transient MOX core Lack of high-order reference to assess absolute performance All nodal results almost identical, the only significant difference can be seen in pin power prediction due to differences in pin power reconstruction methods 1 node per FA discretization is not sufficient for MOX core even with advanced nodal methods (ANM) The difference between 1/FA and 4/FA is small but noticeably improves results It was found that the group effect is not very significant for this problem Negligible difference at static conditions The difference between 2G diffusion and 8G diffusion is 17% for peak power and 7% for power integral Code improvement needs High order heterogeneous transport transient capability 26

27 Benchmark Schedule December 2002: - Distribute first draft specifications February 2003: - Obtain participant s comments March 2003: - Implement participant s comments into specifications April 2003: - Recalculate benchmark May 2003: - Distribute final draft of the specifications - WPPR14: finalize specifications and schedule August 2003: - Provide any additional data for the benchmark December 2003: - Release 2nd revision with all comments February 2004: - Request preliminary results for WPPR meeting March 2004: - Prepare final 8 group xsec set August 2004: - Request for final results September 2004: - WPRS01: final results from 4 participants October 2004: - Request final results before end of the year December 2004: - Generate final DeCART reference June 2005: - WPRS02: close benchmark January 2006: - submit final report for participants review January 2006: - WPRS03: present final report December 2006: - publish final report 27